Conventional food service containers for serving or storing food are well known. The prior art is replete with such containers; one preferred container being disclosed in U.S. Pat. No. 5,377,860 to Littlejohn et al. In the '860 patent there is disclosed a food container which is a combination of a base portion and a lid portion made of a resilient polymeric material. The base is a unitary component including an upwardly projecting, peripherally extending sealing rim having inner and outer sealing areas. The lid is also a unitary component including a peripherally extending sealing channel correspondingly shaped to receive the sealing rim of the base and particularly, to engage the rim at the inner and outer sealing areas. Because both the base and lid are made from a resilient material, the inner and outer sealing materials are shaped to provide a self-reinforcing seal configuration wherein the initial engagement of either the inner or the outer seals urges the other seal into engagement. This feature can accommodate a good degree of tolerance of variations in the dimensions of the lid and the base which are occasioned by variances in the caliper of the substrate.
Various designs have also been proposed for nestable food containers which are reversible to define a lower portion and an upper portion. There is disclosed, for example, in U.S. Pat. No. 5,036,980 to Vigue et al. a nestable food container which is reversible to define a dish or a cover in a composite container. A male and female locking arrangement is provided on the container together with a stabilizing system of protrusions and depressions to stabilize the locked container engagement.
In U.S. Pat. No. 4,974,738 to Kidd et al. there is shown a container provided with a tray component and an independent cover component which is adapted to assume open and closed modes with respect to the tray component. The components are interchangeable and each is provided with a recessed center portion having a base delimited by an angularly extending wall. An edge of the wall defines an open side. Each component also includes a laterally extending rim protruding outwardly from the wall edge. A predetermined first portion of the rim is provided with a first lock member and a predetermined second portion of the rim is provided with a second lock member. When the components are in the closed mode, the first lock member of the tray component is in interlockable engagement with the second lock member of the cover component and vice versa.
In U.S. Pat. No. 4,360,118 to Stern there is disclosed a self-mating pizza pie container. The container includes a pair of circular, shallow container lower and upper half sections, integrally molded of a lightweight, thermally insulating material. Formed along their peripheral sidewalls are mutually interfitting and interlockable means which are configured to be readily releasable for uncovering a contained pizza. Each half section has in its peripheral rim a diagonally opposed locating pin and locating recess for the interfitting reception of the complemental locating and pin recess of the companion half section for relative rotational locating of the two half sections.
U.S. Pat. No. 4,195,746 to Cottrel discloses a food container for the storage and transport of food; especially a hot food such as pizza. The container includes identical upper and lower portions each portion having a flat base surface, outwardly extending sidewalls and a circumferential lip thereabout. A locking portion is carried on the lip to releasably lock the upper and lower portions together. A plurality of vertical honeycombs on the interior of the base surface and a plurality of buttresses are formed in the interior sidewalls.
U.S. Pat. No. 4,294,371 to Davis discloses a food container; in particular, a sundae dish having a bottom dish and a cover that are identical. The rim structure of each part is part male and part female. Each dish is provided with a locking element. The two parts of the container are self-aligned by virtue of the rim structures so that when one is inverted on the other the locking elements are aligned for convenient locking of the container.
U.S. Pat. No. 3,704,779 to Nigg discloses a food tray made of a plastic material with integral break off cutlery. The device includes a substantially rectangular receptacle portion for containing food items and free cutlery pieces protected by a surrounding reinforced frame and arranged so they can be easily broken off by a user. Moreover, the tray maybe detachably secured to another tray to form a closed container as is noted in Column 2, line 38 and following.
In U.S. Pat. No. 3,664,538 to Fioretti there is disclosed a nestable food receptacle including a bottom and plurality of upstanding ear members on the periphery of the bottom member. First ear members alternate in position on the periphery with the second ear members. The receptacles when engaged to one another form a container having a cavity between the bottom members of the receptacles defined by the vertical dimension of the walls of the ear members.
U.S. Pat. No. 3,620,403 to Rump discloses a thin wall thermoplastic container which includes identical dish and cover portions. Each portion has a peripherally extending flange for supporting the other when one is placed on the other to form the assembled container.